bug with the tree widget and collapsed expandable cck fieldgroup

Hi,

When we use a collapsed tree in a collapsed fieldgroup, the tree is expanded with the wrong plus/minus icons. I found the problem and It is a jquery bug in fact, but it affects this module. The way to fix it is replacing a line in js/tree.js

87: $(expandableParent).parent("li.expandable, li.lastExpandable").children("ul").hide();

by this line

87: $(expandableParent).parent("li.expandable, li.lastExpandable").children("ul").css("display", "none");

hope this help somebody